An array microphones (or other sensors) can be advantageously used to detect sounds (or other transmitted energy waves) emitted by objects. An advantage of using an array, as opposed to a single such sensor, is that its output can be electronically processed to emphasize sounds from a particular location and to de-emphasize sounds from other locations--in other words, to reduce background noise. One form of electronic processing is beamforming, which makes it possible to electronically "steer" an array by emphasizing sounds from objects as they move from location to location.
For these reasons, a microphone array can be advantageously used to pick up speech in situations such as teleconferences, where hands-free speech acquisition is desired, where there are multiple talkers or where there the talkers are moving. Through the use of beamforming and other such techniques, the array's directivity pattern can be updated rapidly to follow a moving talker or to switch between several alternating or simultaneous talkers.
The increased popularity of multimedia (or video) teleconferencing presents the art with new challenges. In addition to speech, manufacturers and service providers must provide conference participants with quality images of one another. Conventionally, only single, fixed camera installed at each site to obtain those images. This is problematic where there are more than a few conferees, especially, where those conferees are situated around a large area (e.g., a conference table) or are pacing about.
An object of this invention is to resolve this and related problems by providing methods and apparatus for steering cameras used in a teleconferencing system. A still more particular object is to provide such systems as will automatically steer the camera toward an active talker in the teleconference.
A more general object of the invention provide improved methods and apparatus for locating a source that emits sounds, or other such energies.
Still another object of the invention is to provide source localization systems that can be readily and inexpensively implemented using current digital data processing and/or signal processing technologies.
Yet another object is to provide such systems as can be readily implemented in connection with beamforming or other such steering circuitry.